Using my gears correctly?

[jimboalee]

User3143, Yes it is personal preferences. Your own preference will be dictated by the ratio of 'Fast twitch' and 'Slow twitch' muscle fibres you have. Blame your Dad for this.
Jan's coach assessed he had more Fast twitch fibres which gave him the advantage when he extended his legs slowly. Lance's coach spotted Lance's Slow twitch legs which are better at high repetition, long duration exercise.
Don't worry about yourself. Your physiology will naturally sort your most efficient cadence.
Don't try to copy your favourite Pro. A lot of bad golfers do this.

 

[mickle]

A note about cadence. You can either, 1/ push hard slowly on a higher gear relying on Torque to get the pedals round, or 2/ spin a faster cadence and rely on RPM to produce the power.

The equation is :- (Torque [Nm] x RPM) / 9459 = Power [kW].

You can measure how much power you need by performing a downhill freewheel. Assess your cross section area, the tyre drag coefficient, your vehicle mass and the slope you are descending. Freewheel down and record the fastest speed attained.

If you are really interested, send me a private mail.

From this, you can calc' your Cd. Using Cd, you can calc HP and then kWatts. This is for level ground with no wind speed.

Calculate the gearing on your bike, remembering to couple the correct sprockets with the appropriate chainring. Construct a chart of the cadence required to achieve a speed in each gear.
Associate the power per speed with the cadence in each gear. I find that 130 Watts will be 80ish cadence in a 71" gear for 16 mph. That will get me through an Audax Rando.

Going further, you can approximate calorific expenditure from accumulated power exertion.

In this country, riding a basically circular route, hills are inconsequential and don't need to be considered.

With this post you are spoiling us Ambassador.

 

[swee'pea99]

While understanding the importance of cadence (and the related principle of 'spin don't grind, which certainly works for me), I have never bothered to calculate my cadence, and don't give a monkeys what it is. I know what 'feels right', and that's all you need to know. (If it feels too hard/too slow, change down - how technical is that?)

To answer your query about the smaller front chainset cog, I personally use it all the time, for two specific purposes: one, approaching lights or other situations where I know I'm going to have to slow down or stop - it's the simple way to do a quick 'step-change' down, to make it easier when starting off again; and two, for going uphill.

(In a related issue - given that you 'never use your smaller front' - you do know, I trust, that if you use your big front cog in combination with your biggest back cog (aka 'first') you get your bum smacked and sent to bed with no tea, don't you? It is generally considered a Very Bad Thing. Something to do with wicked elves and mechanical wear... google it if you want to know more.)

 

[fofo]

[quote name='swee'pea99']While understanding the importance of cadence (and the related principle of 'spin don't grind, which certainly works for me), I have never bothered to calculate my cadence, and don't give a monkeys what it is. I know what 'feels right', and that's all you need to know. (If it feels too hard/too slow, change down - how technical is that?)[/quote]

my view exactly and I personally hate spinning away I much prefer put a little more effort into each rotation

 

[jimboalee]

Yes, I read your post.
Athough my post began with a reference to you, the comments at the end were addressed to the originator of the thread. I should have made that clearer. My apologies.

User3143, your words are wise.

All other readers, Listen to User3143, he has wise words.

 

[lantern rouge]

(In a related issue - given that you 'never use your smaller front' - you do know, I trust, that if you use your big front cog in combination with your biggest back cog (aka 'first') you get your bum smacked and sent to bed with no tea, don't you? It is generally considered a Very Bad Thing. Something to do with wicked elves and mechanical wear... google it if you want to know more.)

Thanks again, I hadn't considered Mech wear and tear, just human! - that penny has now dropped

Thanks again everyone for their help in this discussion

 

[jimboalee]

Running the chain from the big ring to the largest sprocket is called 'crossing up'. It is not necessarily to do with chain wear, as the chain should have that much play anyway, but to do with showing your bicycle knowledge. If you calc the ratios, you will see there is a similar ratio using the small ring and a lesser toothed sprocket.

Bike builders choose the chainset and cassette to provide a smooth progression of gear ratios. The two largest sprockets will not be used with the big chainring, and the two smallest sprockets will not be used with the inside chainring/s. You have to do some calcs and chart them to assess where the steps are.
An 'Alpine' chainset of 53 and 39, is a 'Double step' chainset because when the chain is transferred to the other ring, the chain should be moved two sprockets to find the next gear.
A 52, 42 chainset is a 'single' step.
A 'Compact' is an Alpine with smaller rings. 50, 34 ??